Note: The 1048_0B is identical to the 1048_0, except that it comes pre-assembled in a plastic shell enclosure and you have the option of which length of USB cable you want to include.

Thermocouples are widely used to measure extreme temperatures impossible to measure with other types of sensors.

J, K, E and T thermocouples are directly supported in the library and return the measured temperature in °C.

It is possible to interface other thermocouple types by converting the measured potential returned by the Temperature Sensor into Celsius using the appropriate tables; the formula and links to the tables are described in the 1048 User Guide.

Very long thermocouples are okay (even 100m), but if there is measurement stability issues or USB resets, ferrite beads can be added to the thermocouple wire close to the Phidget Temperature Sensor. See our tutorial on Addressing EMI Issues.

Thermocouples

You can connect up to four J,K,E or T type thermocouples to this Phidget. See the product page or data sheet for the thermocouple to determine which end plugs into the positive terminal on the Phidget. If you're not sure which end is which, it won't harm anything to try both configurations to determine which one is right. If the thermocouple is hooked up backward, you'll get erratic readings and the temperature will decrease when it should be increasing.

USB Cables

Use a USB cable to connect this Phidget to your computer. We have a number of different lengths available, although the maximum length of a USB cable is 5 meters due to limitations in the timing protocol. For longer distances, we recommend that you use a Single Board Computer to control the Phidget remotely.

The measured temperature will be updated next to the Temperature label. Touch the thermocouple wire with your hands to see the temperature increase. If the temperature decreases when it should be increasing, you may have the wires plugged in incorrectly.

Temperature Sensor (IC)

Double-click on the Temperature Sensor object , labelled Temperature Sensor (IC), in order to run the example:

General information about the selected object will be displayed at the top of the window. You can also experiment with the following functionality:

Modify the change trigger and/or data interval value by dragging the sliders. For more information on these settings, see the data interval/change trigger page.

The measured temperature can be seen next to the Temperature label. Cover the board with your hands to see the temperature quickly rise.

Voltage Input

Double-click on the Voltage Input object in order to run the example:

General information about the selected object will be displayed at the top of the window. You can also experiment with the following functionality:

Modify the change trigger and/or data interval value by dragging the sliders. For more information on these settings, see the data interval/change trigger page.

Finding The Addressing Information

Before you can access the device in your own code, and from our examples, you'll need to take note of the addressing parameters for your Phidget. These will indicate how the Phidget is physically connected to your application. For simplicity, these parameters can be found by clicking the button at the top of the Control Panel example for that Phidget.

In the Addressing Information window, the section above the line displays information you will need to connect to your Phidget from any application. In particular, note the Channel Class field as this will be the API you will need to use with your Phidget, and the type of example you should use to get started with it. The section below the line provides information about the network the Phidget is connected on if it is attached remotely. Keep track of these parameters moving forward, as you will need them once you start running our examples or your own code.

Using Your Own Program

You are now ready to start writing your own code for the device. The best way to do that is to start from our examples:

Once you have your example, you will need to follow the instructions on the page for your programming language to get it running. To find these instructions, select your programming language from the Software Overview page.

Technical Details

Cold Junction Compensation and Self-heating

Thermocouples consist of two junctions, one where the thermocouple meets the Phidget and one where the two wires are welded together at the sensing end of the device. In simplified terms, a thermocouple works by detecting the temperature difference between these two junctions. As such, in order to measure the temperature at the sensing end we need to know the temperature where the thermocouple connects to the Phidget. To do so, there is an ambient temperature sensor on the board.

An important thing to note is that the ambient temperature sensor measures the temperature of the board and the air around it, though not specifically at the junction. Generally you can assume they are nearly the same temperature, however as the electronics heat up by being powered on there can be some small error introduced. This is exacerbated by having the board in an enclosed space where normal airflow is restricted thereby increasing the effect of self-heating. As a result we recommend that the board be left in as open and well ventilated/cooled a place as possible to minimize this error source.

What to do Next

Phidget22 API - The API is a universal library of all functions and definitions for programming with Phidgets. Just select your language and device and it'll give you a complete list of all properties, methods, events, and enumerations that are at your disposal.

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Phidgets Inc.

We believe in getting problems solved quickly and projects finished on time. That's why we specialize in making affordable, easy to use sensors and controllers that require minimal electronics knowledge.

Phidgets Inc.

We believe in getting problems solved quickly and projects finished on time. That's why we specialize in making affordable, easy to use sensors and controllers that require minimal electronics knowledge.